Right two photos - pulled or wormed Williams Cleaner Type III, dug Kennesaw Mountain, Ga.
Bullet was invented to help clean the bore of rifles from black powder fouling that built up from frequent firing. The zinc insert scraped the bore upon firing. Type III was issued in the later part of the war (1864) and is the most common recovered from Civil War sites by relic hunters. They were initially wrapped in blue paper and commonly issued one in ten cartridges. Some Union soldiers did not feel that they were accurate and would discard the Williams cartridges. Government switched from blue wrapper to buff colored. Testing did confirm that they were indeed accurate rounds. Many Confederate soldiers called them "poison" bullets. They believed that the zinc inserts would cause poisoning and accelerate gangrene in the bullet wounds.